<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Animating symbols</title>
    <link href="/maps/documentation/javascript/examples/default.css" rel="stylesheet">
    <script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
    <script>
var line;

function initialize() {
  var mapOptions = {
    center: new google.maps.LatLng(20.291, 153.027),
    zoom: 6,
    mapTypeId: google.maps.MapTypeId.TERRAIN
  };

  var map = new google.maps.Map(document.getElementById('map-canvas'),
      mapOptions);

  var lineCoordinates = [
    new google.maps.LatLng(22.291, 153.027),
    new google.maps.LatLng(18.291, 153.027)
  ];

  var lineSymbol = {
    path: google.maps.SymbolPath.CIRCLE,
    scale: 8,
    strokeColor: '#393'
  };

  line = new google.maps.Polyline({
    path: lineCoordinates,
    icons: [{
      icon: lineSymbol,
      offset: '100%'
    }],
    map: map
  });

  animateCircle();
}

function animateCircle() {
    var count = 0;
    window.setInterval(function() {
      count = (count + 1) % 200;

      var icons = line.get('icons');
      icons[0].offset = (count / 2) + '%';
      line.set('icons', icons);
  }, 20);
}

google.maps.event.addDomListener(window, 'load', initialize);

    </script>
  </head>
  <body>
    <div id="map-canvas"></div>
  </body>
</html>